Apparatus for coating articles



Oct. 31, 1939. c, AULBACH 2,178,158

APPARATUS FOR COATING ARTICLES Filed April 29, 1937 Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR COATING ARTICLES Application April 29, 1937, Serial No. 139,812

1 Claim.

The present invention relates to new and useful improvements in an apparatus for coating articles and more particularly to an apparatus for coating the interior surfaces of can bodies and the like.

An object of the invention is to provide an apparatus for coating articles wherein a chamber having relatively movable wall portions is provided for receiving a coating liquid and wherein the coating liquid is forced into contact with the surface of the article to be coated by relative movement of the wall portions of the chamber toward one another.

A further object of the invention is to provide an apparatus of the above type for coating the interior surfaces of can bodies or the like wherein the can body is formed as a continuation of the liquid chamber and is movable with one of the wall portions to cause the liquid to flow by pressure into contact with the interior surface thereof.

A still further object of the invention is to provide an apparatus of the above type wherein the can body serves not only as a portion of the liquid chamber, but also as a means by which pressure is transmitted to the movable wall portion of the chamber whereby to apply pressure to the coating liquid to force the same into contact with the interior surface of the can.

The above and other objects of the invention will be obvious and will be hereinafter more fully pointed out.

In the drawing:

Figure 1 is a side View in section showing an apparatus for coating the interior surface of a can body before the coating liquid has been forced into contact with the can body.

Figure 2 is a similar sectional view showing the apparatus when the coating liquid is in contact with the interior surface of the can body.

Figure 3 is a fragmentary sectional view showing a similar apparatus for coating the interior surface of a cone top end of a can.

Heretofore, it has been customary to coat the interior surfaces of can bodies by applying pneumatic pressure to a bath of coating material, usually in liquid form, and forcing the liquid into the can body, or by creating a vacuum in the can body and thus drawing the coating liquid upwardly therethrough so as to coat the interior surface thereof. In carrying out the above methods, it is necessary to provide somewhat complicated machinery for creating the pressure or vacuum, as the case may be. According to the present invention, the coating material is mechanically forced into contact with and progressively over the interior surface of the can body. Direct mechanical pressure is applied to the bath of the coating material so that it is forced into contact with the surface of the article to be coated. The application of pressure in this manner results in a quick and substantially instantaneous movement of the coating liquid into contact with the surface to be coated.

In the illustrated embodiment of the invention, the coating liquid is confined in a chamber having relatively movable wall portions, one of which is adapted to support the can body with the inner surface thereof in communication with the chamber. The can body is supported on the wall portion so as to form an extension or continuation of the chamber containing the coating material. Pressure is transmitted to the movable wall portion of the chamber, and the resulting movement of the wall portion creates an internal hydraulic pressure in the bath of coating material which is forced upwardly into contact with and progressively over the interior surface of the can body. When pressure is released, the movable wall portion returns to its normal position and the coating material flows back into the chamber, leaving a thin coating of the material on the interior surface of the can body.

Referring more in detail to the accompanying drawing, one embodiment of an apparatus employed for carrying out the method is illustrated. The apparatus, as shown, is provided with a base portion which includes a stationary member If! mounted on a plate I I and secured thereto by bolts I2 or the like. The member ID is provided with a central aperture I3 communicating with an aperture I4 in the plate II. The upper end of the member ID is provided with an outwardly eX- tending annular portion I5, providing at the lower edge thereof a shoulder I500. A movable wall portion is mounted on the member In and includes a peripheral wall I6 which is in liquidtight contact with the outwardly extending portion I5 on the member II]. A plate I'I, having a central aperture Ila therethrough, is secured by bolts I8 or the like to the peripheral wall portion I6. The plate H, the peripheral wall portion I6, and the stationary member If! thus form a partially closed chamber for receiving the coating liquid C. The lower edge of the peripheral wall portion I6 is provided with an inwardly extending peripheral shoulder I9 which underlies the shoulder I5a on the member Ill. Springs 29 are disposed between the bottom edge of the peripheral wall portion I6 and suitable locating recesses 2I in the plate II. The springs 20 tend to normally force the movable wall portion upwardly, this upward movement being limited by contact between the shoulders l9 and la. A valve or plug 22 is employed for closing the aperture M in the plate H.

The plate H is provided with a groove around the opening Ha therethrough and a gasket 23 or other suitable sealing material is disposed therein. In Figs. 1 and 2 of the drawing, a can body 13 is shown with the outwardly flanged end 2d thereof disposed in sealed contact with the gasket 23 and forming a continuation of the opening [1a through the plate ll. Thus, the can body communicates with the chamber holding the coating liquid. A movable member 25 in the form of a piston or plunger is disposed above the opposite end of the can body B and is provided with a sealing gasket 26 against which the opposite flanged end E la of the can body is disposed in sealed contact. The movable member 25 carries a tube 23 which extends therethrough so that it is in communication with the atmosphere and with the interior of the can body B. The tube 2! may be made of glass or the like so that the level of the coatin liquid may be seen therethrough.

In the operation of the apparatus, pressure is applied to the movable member 25 and this pressure is transmitted by the can body B to the movable wall portion, constituted by the plate H and the peripheral wall l5, so that downward movement of the member '25 causes a corresponding downward movement of the wall portion against the action of the springs rill. As shown in Fig. 2, the downward movement of the wall portion will force the coating liquid upwardly through the can body and into the tube 2'1. When pressure is released from the member 25, the springs will cause the return of the movable wall portion to the position shown in Fig. 1 so that the coating liquid will recede from within the can body and leave a thin coating adhering to the inner surface thereof.

As shown in Fig. 3, a similar apparatus is employed for coating the inner surface of a cone top end T for a can body. In this form of the apparatus, the plate Ila is provided with an upwardly extending annular portion 28 which extends into the annular channel 29 usually formed on a can end. The movable member a is shaped to rest on the open end of the nozzle of the can end T. Similar downward movement of the member 25a will cause downward movement of the movable wall portion and the can end T so that the end may be coated in a manner similar to that shown and described in connection with Figs. 1 and 2.

It is to be clearly understood that minor changes in the details of construction and arrangement of parts may be made without departing from the scope of the invention as set forth in the appended claim.

I claim:

An apparatus for coating the interior surfaces of sheet metal can bodies comprising a base having an outwardly extending annular shoulder adjacent the upper end thereof, a sleeve sur-- rounding said base and having a liquid-tight connection therewith and also having an inwardly projecting annular shoulder adapted to contact with the shoulder on said base, springs between the sleeve and the base for normally holding the sleeve in a raised position thus forming a chamber in the sleeve, the upper or" the base forming the bottom of said chamber, a cover plate attached to the sleeve and closing the chamber,

said cover plate having an opening therethrough and a gasket seat surrounding the opening at the upper side thereof. a gasket on said seat on which. the body to be coated is supported, a cover member having a gasket adapted to engage the upper end of the can body and close the same, 

